Arynes are highly electrophilic reactive intermediates, which have been extensively utilized in various carbon-carbon and carbon-heteroatom bond-forming reactions. Arynes have been employed for the construction of multisubstituted arenes of structural diversity and complexity. This kinetically unstable intermediate can react with a wide variety of anionic and uncharged nucleophiles leading to a direct approach to access 1,2-disubstituted arenes, which are structural fragments in many natural compounds as well as biologically active compounds.
Hence the process for the preparation of these compounds and newer forms is an area of continuous research. One of the important aspects of aryne chemistry is multicomponent reaction, which mainly include the initial addition of nucleophiles to arynes and subsequent trapping of the aryl anion intermediate with electrophiles. If the nucleophile and electrophile do not belong to the same molecule, the overall process is a unique three-component coupling, where the aryne is inserted between the other two coupling partners [eqn (1)]. This versatile transition-metal-free methodology has been applied to the synthesis of valuable heterocycles and in natural product synthesis.

The synthesis of spirooxazine compounds using transition metal and heterocyclic compound as nucleophile is reported in the art.
KR970005311 discloses process for preparing spirooxazine compounds, comprising reacting indoline or indolinium derivatives with nitroso arene derivative to produce spirooxazine compounds characterized in that amine complex of transition metal is used as catalyst.
One-Pot Synthesis of Photochromic 6′-Amino-Substituted Spirooxazines from 1-Nitroso-2-naphthol Zinc Chelate and Indoline Base is disclosed by Pang, Mei-Li et al. in Synthesis; 2010, 20; 3418-3422. U.S. Pat. No. 4,785,097 describes process for synthesizing a spiro-type compound comprising mixing an unsubstituted or substituted first compound selected from the group consisting of 2-methyleneindoline, 2-methylenebenzothiazoline, 2-methylenebenzoxazoline, or a halide salt thereof and a metal chelate of either an ortho-hydroxynitrosoaromatic compound or a substituted ortho-hydroxynitrosoaromatic compound, the aromatic compound selected from the group consisting of benzene, naphthalene, coumarin, quinoline, isoquinoline benzofuran, benzoxazine, isocoumarin, benzopyran, pyridine or chromone, in a solvent at temperatures sufficient to cause reaction of the first compound and the metal chelate.
US20100280241 describes Spirooxazine radical derivatives and reversible isomerization reaction, where 5-member or 6-member heterocyclic ring and an oxazine derived heterocyclic ring form a Spiro structure and an oxygen radical binds to the nitrogen of the 5-member or 6-member heterocyclic ring adjacent to the spiro-carbon.
Article titled “The Three-Component Reaction between Isatin, α-Amino Acids, and Dipolarophiles” by Stanley Rehn et al. in European Journal of Organic Chemistry Volume 2004, Issue 2, pages 413-418, January 2004 discloses preparation of 3-Spiro[pyrrolidino-oxindoles] from a three-component reaction between isatin, an α-amino acid, and a dipolarophile.
Multicomponent reaction using aryne is known in the art, but utilizing N-heteroaromatic compounds as the nucleophilic trigger is very rare. However, the inventors developed novel biologically active spiro-oxazino and indolinone compounds and economically and industrially feasible process for preparation thereof, wherein the process is transition-metal free and multicomponent reaction to afford high yield and selectivity of desired products.